The storage and disposal of sewage sludge from municipal wastewater treatment plants is becoming an increasing problem on a global scale. The attention of scientists is directed to the search for unique technologies to manage them. Firing sewage sludge in furnaces and producing lightweight aggregates and granules constitutes an innovative method of its disposal. The resulting granules could be a substitute for commonly used materials such as perlite, vermiculite, expanded clay, or LSA, and could be used as a secondary material in the construction industry, including road construction, as various types of ballast, and as an equivalent to aggregate in concretes. However, given that sewage sludge is increasingly used in biogas production, it does not completely decompose in the process and is still a problematic waste for many municipal treatment plants. Therefore, the use of sewage sludge pellets in construction, or any other industry, could revolutionize the market. The purpose of the conducted research was to evaluate the heat-insulating properties of granules produced from sewage sludge from the Municipal Wastewater Treatment Plant "Łyna" in Olsztyn used as a heat-insulating material.